Accident Details
During water ingestion tests requiring multiple landing rolls through a diked pool on the runway, a Learjet executed a landing roll in which the left main landing gear and nose landing gear tracked through the pool while the right main landing gear tracked outside. The airplane subsequently veered left, departed the left side of the runway, and struck a pickup truck parked adjacent to the runway. After the collision, the airplane came to rest inverted and on fire.
Pre-Test Procedures
Formal hazard identification and risk management procedures were not employed for the test. Additionally, no alignment cues were placed on the runway to assist the pilot in aligning the aircraft with the water pool. During the test, the accident truck, other vehicles, heavy equipment, and personnel were positioned hundreds of feet inside the FAA-recommended runway-safe and object-free areas.
Probable Cause and Factors
The official probable cause was the failure of the pilot to obtain or maintain alignment with the water pool, which resulted in a loss of control. Factors in the accident were the inadequate preflight planning of the flight test facility and the airplane manufacturer, which resulted in hazards in the test area and the subsequent collision of the airplane with a vehicle.